World population at 8 billion

UNITED NATIONS, United States (AFP) — The United Nations Population Division estimates that the number of humans on Earth will grow to eight billion on 15 November, more than three times higher than the 2.5 billion global headcount in 1950.

However, after a peak in the early 1960s, the world's population growth rate has decelerated dramatically, Rachel Snow of the UN Population Fund told AFP.

Annual growth has fallen from a high of 2.1 percent between 1962 and 1965 to below 1 percent in 2020.

That figure could potentially fall to around 0.5 percent by 2050 due to a continued decline in fertility rates, the UN projects.

When will we peak?

Given the increase in life expectancy as well as the number of people of childbearing age, the UN projects the population to continue growing to about 8.5 billion in 2030, 9.7 billion in 2050, and a peak of about 10.4 billion in the 2080s.

Other groups have, however, calculated different figures.

The United States-based Institute for Health Metrics and Evaluation estimated in a 2020 study that the global population would max out by 2064, without ever reaching 10 billion, and decline to 8.8 billion by 2100.

"We are lower than them (the UN) and I think we have a good reason," lead author of the IHME study, Stein Emil Vollset, told AFP.

The University of Washington professor says that under their "quite different fertility model," the human population will only reach somewhere between nine and 10 billion.

Fertility rate drop

In 2021, the average fertility rate was 2.3 children per woman over her lifetime, down from about five in 1950, according to the UN, which projects that number to fall to 2.1 by 2050.

"We've reached a stage in the world where the majority of countries and the majority of people in this world are living in a country that is below replacement fertility," or roughly 2.1 children per woman, says Snow.

A key factor driving global population growth is that average life expectancy continues to increase: 72.8 years in 2019, nine years more than in 1990. And the UN predicts an average life expectancy of 77.2 years by 2050.

The result, combined with the decline in fertility, is that the proportion of people over 65 is expected to rise from 10 percent in 2022 to 16 percent in 2050.

This global graying will have an impact on labor markets and national pension systems, while requiring much more elderly care.